My dh runs his own business and essentially it's just him. He does have some freelancers he can use. He is essentially self employed. He works whatever hours he wants. Sometimes it might be 7am til 10pm, other times it might be 9-5. He never takes holiday unless nagged and nagged and we often need to cancel/rearrange if a job comes in.
We had plans for an upcoming weekend and he's decided to accept a large job that will take him out the house for 4 days to a foreign country including the weekend. Messing up our plans. We frequently have weekends where he works one day. He's always on his phone or laptop of an evening.
Here's the problem, I have just returned to work following maternity leave. We are juggling three young children. I take 1.5 days off and he takes an afternoon off. I will soon need to do two pick ups and drop offs and I have 20 minutes to essentially be in two places at once. I am barely earning anything working across 4 days as you can imagine nursery fees for three children.
His business does not allow me to give up work. He doesn't earn enough. I have a decent job and have good earning potential. He seems to snub this saying things like "we could afford nice things if you let me work at weekends" 
Aibu to not be happy at the prospect of repeatedly dealing with the kids by myself and getting no family time at weekends? He is unreliable in a sense because I can't rely on him to always be free on a certain day. So for example it's pointless booking swimming lessons for my eldest on Saturday as I simply can't look after three kids alone.
He thinks I'm being massively unreasonable as I'm stopping his business growing. But it's been like this for 10 years. Only it didn't matter then as we didn't have three children. It's not grown over that time, there are no more employees... it's just him.